What are the Arduino micro and Pro micro board?

Arduino Pro Micro (Clone) Not Recognizable - IDE 1.x - Arduino Forum

PRO Micro Atmega32u4 5V / 16MHz Mini MCU Leonardo Board for Arduino - China PRO Micro, Atmega

SparkFun 12640 Pro Micro - 5V/16MHz

Arduino Pro Micro, ATMega32U4 Arduino Board

The case of the broken Pro Micro – gr33nonline

Introduction to Arduino Pro Micro - The Engineering Projects

Ks0249 keyestudio PRO MICRO Development Board - Keyestudio Wiki

Reinstall bootloader for an Arduino Pro Micro?

The Inland PRO MICRO is a microcontroller board based on the ATMEGA32U4-MU. It is an easy-to-use open source hardware and is fully compatible with Arduino. This board offers 18 GPIO and 9 analog input pins as well as SPI and I2C serial communication.

Inland Pro Micro Development Board Arduino Compatible KS0249

Pro Micro & Fio V3 Hookup Guide - SparkFun Learn

What is Arduino Pro Micro: a Comprehensive Introduction for Novices